Struct Budget 

pub struct Budget { /* private fields */ }

Mutable per-execution counters for one script run.

Implementations

impl Budget

pub fn start(limits: Limits) -> Self

Starts a fresh budget and its wall clock.

pub fn charge_step(&mut self) -> Result<(), LimitExceeded>

Charges one evaluation step and re-checks the deadline.

This is the only backstop against while true; do :; done. The deadline is re-read on every step rather than every Nth: a script can spend minutes in very few steps (a handful of slow capability calls, one enormous string concatenation), so a sampled clock leaves the exact workloads that most need bounding unbounded. Reading a monotonic clock costs tens of nanoseconds against a tree-walking step that costs far more.

pub fn charge_value_bytes(&mut self, bytes: u64) -> Result<(), LimitExceeded>

Charges value bytes a script materialized into a variable, buffer, or capture.

This counter is deliberately cumulative rather than retained: it bounds how many bytes a script may bring into existence over its whole run, not how many it holds at one instant. Retained memory is always at most the cumulative total, so a cheap bound on the total is a sound bound on the peak, and it needs no release path that a missed call could silently corrupt. Without it, x="$x$x" repeated twenty-six times reaches gigabytes in a few hundred steps — every other ceiling here counts operations, and none of them counts bytes.

pub fn check_deadline(&self) -> Result<(), LimitExceeded>

Re-reads the wall clock immediately.

pub fn remaining(&self) -> Duration

Returns the time left before the deadline trips.

pub fn enter_call(&mut self) -> Result<(), LimitExceeded>

Enters one shell-function frame.

pub fn leave_call(&mut self)

Leaves one shell-function frame.

pub fn charge_capability_call(&mut self) -> Result<(), LimitExceeded>

Charges one capability invocation.

This counter is deliberately independent of the step budget: a single script can loop and drive many capability calls where one model tool call drives exactly one today, so the amplification vector needs its own ceiling.

pub fn capability_calls(&self) -> u32

Returns the number of capability invocations charged so far.

pub fn steps(&self) -> u64

Returns the number of steps charged so far.

pub fn value_bytes(&self) -> u64

Returns the value bytes charged so far.

Trait Implementations

impl Debug for Budget

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.